Mathematical modeling of maltose hydrolysis in different types of reactor

Abstract

A commercial enzyme Dextrozyme was tested as catalyst for maltose hydrolysis at two different temperatures: 40 and 65°C at pH 5.5. Its operational stability was studied in different reactor types: batch, repetitive batch, fed-batch and continuously operated enzyme membrane reactor. Dextrozyme was more active at 65°C, but operational stability decay was observed during the prolonged use in the reactor at this temperature. The reactor efficiencies were compared according to the volumetric productivity, biocatalyst productivity and enzyme consumption. The best reactor type according to the volumetric productivity for maltose hydrolysis is batch and the best reactor type according to the biocatalyst productivity and enzyme consumption is continuously operated enzyme membrane reactor. The mathematical model developed for the maltose hydrolysis in the different reactors was validated by the experiments at both temperatures. The Michaelis-Menten kinetics describing maltose hydrolysis was used.List of symbols EC Enzyme consumption (kU g -1 ) K m Michaelis constant (g dm -3 ) k d Enzyme operational stability decay rate constant (min -1 ) q v Flow rate of the reaction solution (cm 3 min -1 ) Q BP Biocatalyst productivity (g kU -1 ) Q p Volumetric productivity (kg dm -3 d -1 )Maximal reaction rate (g dm -3 min -1 )Greek symbols c Concentration (g dm -3 ) u Enzyme concentration expressed as enzyme volume per volume of reaction mixture (cm 3 /cm 3 )

NADH Oxidation in a Microreactor with an Oscillating Magnetic Field

“…If cheap biocatalyst is used, it is appropriate to choose the best reactor mode on the basis of the volumetric productivity. On the other hand, if an expensive biocatalyst is used, it is appropriate to choose between reactors according to the turnover number and enzyme consumption [35]. In order to propose best reactor type, turnover numbers (TON; k cat (/s)) were calculated for reaction performed in different reactor types and results were compared ( Table 1).…”

Operational Stability of Glucoamylase in Continuously Operated Ultrafiltration Membrane Reactor – Experimental Methods and Mathematical Model

“…Thus, the conversion decrease refers to the decrease in enzyme activity and its operational stability decay 15 . The main disadvantage of this method is that the enzyme operational stability decay can go undetected due to high enzyme concentration in the reactor, which was seen in previous research of the system in question 16 . To avoid such a problem in this research, enzyme activity was followed directly in the reactor and parallel and independently of substrate conversion.…”

“…The results are presented in Figure 3a. In the previous research 16 the reaction at 40 °C was monitored over 35 days and the stationary maltose conversion was approximately 100 % during the whole experiment. The experiment at 45 °C (Figure 3a) lasted 40 days and 100 % stationary maltose conversion indicated that the enzyme was stabile, but this was not the case.…”

“…Kinetic model of maltose hydrolysis was developed in previous research 16 using initial reaction rate method and followed Michaelis-Menten kinetics (Eq. 2).…”

A new concept for production of (3S,4R)-6-[(benzyloxycarbonyl)amino]-5,6-dideoxyhex-2-ulose, a precursor of d-fagomine

“…D-Fagomine is a naturally occurring iminosugar which can be found in plants in small quantities. 19 The strategy devised in this work consisted of the simultaneous use of three enzymes: horse liver alcohol dehydrogenase (HLADH) used for the oxidation of N-Cbz-3-aminopropanol (1) to N-Cbz-3-aminopropanal (2), D-fructose-6-phosphate aldolase (FSA) variant A129S for the aldol addition, and a third enzyme; NADH oxidase (NOX) for coenzyme regeneration (Scheme 1). Lactobacillus).…”